Electric interrupting device notably for polyphase limiting circuit breakers



1964 J A c; BIONNEFOIS 3, 7

ELECTRIC IN'TER'RUP'TING DEVICE NOTABLY FOR POLYPHASE LIMITING CIRCUIT BREAKERS Filed Oct. 31, 1958 3 Sheets-Sheet 1 FIG .1

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13 2 O A O 1 'l 24 5 3 W 16 6 4, GENERAL-I) 2 3 ACITU-ATING' MECHANISM INVENTOR JEAN ANDRE GEORGES BONhEFOIS ATTORNEY Oct. 27, 1964 J. A. e. BONNEFOIS 3,154,657

ELECTRIC INTERRUPTING DEVICE NOTABLY FOR POLYPHASE LIMITING CIRCUIT BREAKERS Filed Oct. 51, 1958 3 Sheets-Sheet 2 F|G.2 P 1 k GENERAL ACTUATING MECHANISM :NvENTOR.

JEAN ANDRE GEORGES BONPEFOIS BY Paul 84;

ATTORNEY Oct. 27, 1964 J. A. cs. BONNEFOIS 7 ELECTRIC INTERRUPTING DEV NOTABLY FOR POLYPHASE' LIMITING CIRC BREAKERS Filed Oct. a1, 1958 3 Sheets-Sheet 3 .GENERAL ACTUATING MECHANISM INVENTOR JEAN ANDRE GEORGES BONNEFOIS WM. m. ATTOR United States Patent 3,154,657 ELECTRIQ KNTERRUPTWG EEWQJE NTA- ELY Fill; PEBLYPTASE LTMTTHNG CTRCUET BREAKER Jean Andre Georges Bonnefois, Paris, France, assignor to Compagnie Generals: dElectricite, Paris, France, a corporation of France Filed @ct. 311, 1953, Ser. No. 771;,M6 Claims priority, application France, Nov. 15, 1957, 751,674- 9 (Ilaims. (Cl. 20tl-l47) The invention relates to electric interrupting devices and notably to polyphase limiting circuit breakers.

Apparatus of this type are already known which comprise a polyphase circuit breaker with which fuses are associated. The fuses effect the breaking in the case of heavy overloads, While the circuit breaker acts only in the case of light overloads. These devices are interesting for the protection of electric installations comprising circuits in which very high short-circuit currents may be set up. They limit the short-circuit current to a fraction of the presumed maximum value and thus considerably reduce the electrodynamic and thermal stresses on the equipment. Consequently, the dimensions of the circuit breaker and of the protective circuit, as also the volume of the space in which the circuit breaker is enclosed, can be considerably reduced.

The fuse having high interrupting capacity is an excellent limiter, but is irreversible and the fuse link must be replaced after operation.

The present invention has for its object to provide an interrupting device which has the advantages of the aforesaid device while comprising no fuse.

Generally speaking, the limitation of high over-currents by an ultra-rapid circuit breaker is effected by the creation of a considerable breaking arc voltage at the break well before the current has had time to reach the presumed maximum value. The current is immediately stopped in its growth and rapidly decreases until it is extinguished. In the case of heavy overloads, the current value corresponding to the appearance of the arc is that at which the contacts are repelled by electrodynamic effect. The repulsion depends upon the shape and the pressure of the contacts. The most effective limitation will correspond to the lowest repulsion current compatible with correct operation of the device. The great difficulty resides in obtaining a very short release time for the pole subjected to the short-circuit with the object of facilitating the development of the arc and avoiding any reclosing of the contacts at the passage of the current through Zero.

The present invention has precisely for its object to provide an ultra-rapid tripping device associated with each pole, which permits pole-by-pole opening in the event of a short-circuit. The device comprises for each pole a movable contact and a support or carrier therefor having a means for locking the movable contact carrier or contact cage and an electro dynamic tripping device whose operation results in the breaking of the locking action and the release of the movable contact carrier or contact cage and thus the opening of the pole. The operating threshold of the tripping device is so adjusted as to avoid any untimely tripping in the case of normal working overloads.

For operations other than those of opening on shortcircuit, all the poles of the circuit breakers are simultaneously driven in known manner through the general mechanism of conventional construction.

In the case of heavy overloads in one or more poles, the ultra-rapid tripping devices effect the opening of these poles independently of one another. The breaking of the locking action on each of the poles requires only a small movement of the corresponding tripping device, the moment of inertia of the movable part being reduced to the lowest permissible value. In order to effect the separation of the arcing contacts, the movable contact carrier or contact cage alone is set into motion, which constitutes a considerable reduction of the total inertia of the parts to be moved at the opening of the poles. The travel is reduced to the angular movement corresponding to the wiping of the contacts, i.e., the path which the movable contact would undertake if, in the closed position, the corresponding fixed contacts were withdrawn. As a result of all these features, the response of the tripping device is extremely rapid.

At the end of the opening movement of the movable contact carrier or contact cage, the latter encounters a control lever of the linkage for the release of the locking of the general mechanism of the circuit breaker, thus effecting the opening of all the poles of the circuit breaker. The arrangement is such that the lever encountered is retracted at the beginning of the general opening movement of the poles.

Further features and advantages of the invention will become apparent from the description thereof, which is hereinafter given with reference to the figures of the accompanying drawings, which show by the way of example one constructional form of a device according to the invention. The figures are a diagrammatic side elevation of the tripping device provided for each pole and show the device controlling the general mechanism of the circuit breaker.

FIGURE 1 shows the switch in the closed position, FIGURE 2 shows the tripped position of the pole immediately after the operation on short circuit, and FIG- URE 3 shows the tripped and recocked position of the pole which has operated on short-circuit, after complete opening of the switch through the general mechanism.

The device illustrated in the drawings comprises among other elements an electromagnetic tripping device 1 whose coil consists of the conductor 1' of the pole and has the main current flowing therethrough, while the blade 2 of the circuit breaker tripping device is movable about a pin 2" and comprises a return spring 3. The blade comprises at its free end a lever arm 4 which bears on a locking member 5 pivotally mounted on a pin 22 and serving to effectively lock a movable contact 8 with the aid of a hook or nose portion 6 which locks the movable contact carrier or contact cage 7 in the position in which the movable contact 8 and the fixed contact 9 are closed. The movable contact 8 is supported in a conventional manner on the movable contact carrier or contact cage '7 by the interposition of a conventional pressure spring 31 producing the engaging pressure for the full engagement of the movable contact 8 with the stationary contact as is customary. The movable contact 8 is electrically connected to the conductor 1' by means of a flexible electrically conducting member 3' which together with the conductor W connected to the fixed contact 9 and the conductor 1 form a loop within which the effective pivotal axis 32 of the movable contact 8 is located in a manner described hereinafter. Thus, upon the occasion of a short circuit currents to the conductors of this loop, an electromagnetic repulsion force seeks to separate and effects separation of the contacts 8 and 9. The movable contact carrier or contact cage 7 tends to turn about a stationary pivot point, formed by a pin 10, under the action of a spring 11 and comprises an impact member 312 intended to strike and bear against a lever 13 which transmits the movement of the movable contact carrier or contact cage 7 to a driving shaft 14 of the general mechanism of the circuit breaker of any known conventional construction and indicated only schematically in block. In response to this actuation of shaft 14, a

shaft 23 common to all the poles which is operatively connected in a conventional manner with the shaft 14 by way of the conventional general mechanism, is released by the mechanical general circuit breaker operating and reset machanism and the general opening of all the poles of the switch is produced thereby. A mechanical release or reset actuating lever or actuating cage 21 turns about the pin 10 which is fixedly mounted and which is also the pivot of the movable contact carrier or contact cage 7; the locking lever turns about the pin 22 which is fixed on and movable with the actuating lever for actuating cage 21. The actuating lever or actuating cage 21 is connected to a movable arm 16 fixedly mounted on the common shaft 23 of the general mechanism of the circuit breaker of conventional construction by the interposition of an insulator 15 which is pivotally mounted on the movable arm 16 by a pin 24 and on the actuating lever or actuating cage 21 by a pin Ztl which is also the pivot of the lever 13. The members 15, I6, and 21 move in such manner in the case of general opening as to take up the position indicated in FIGURE 3. The contacts 8 and 9 supporting thereon the main contacts 118 and I19 are disposed in a break chamber comprising arcing contacts 118 and 119, arcing contact support 17, arcing horns 18 and an arc chute 19 of the type comprising metal deionising plates, which forms the subject of the French Patent No. 1,157,951 and of its addition filed on June 7, 1957. The US. Patent 2,934,629, issued on April 26, 1960, to I. Bonnefois et al., and assigned to the assignee of the present application corresponds to the French Patent No. 1,575,959. The said chamber has the property of very rapidly setting up a high are voltage determining the limitation of the short-circuit current. The operation of the device hereinbefore described in the event of a heavy over-load is as follows:

7 The blade 2 of the electromagnetic tripping device I is attracted as soon as the momentary or instantaneous value of the current reaches the critical threshold. The blade 2 drives in its movement the lever 4 bearing against the locking member 5 by imparting a counterclockwise torque thereto about pin 22. The disengagement of the hook or nose portion 6 of the locking member 5 releases the movable contact carrier or contact cage 7. As soon as the movable contact carrier 7 has moved through the angle corresponding to the wiping of the contacts, i.e., the path corresponding to the wiping action that the movable contact 8 would carry out toward the right as viewed in the drawing if the corresponding stationary or fixed contacts 9 and 17 were removed, the contacts 8 and 9 are separated. The electrodynamic forces act on the movable part 8, 8 of the pole, which they tend to open; at about the same time, the locking member 6 is disengaged by the electromagnetic attraction of the ultrarapid tripping device 2, 4 so that the electrodynamic forces contribute to a considerable increase of the acceleration of the opening movement of the movable contact carrier or contact cage '7 about the pin It). In the course of the movement, the movable contact carrier or contact cage 7 encounters by means of the impact member 12 the lever 13, which transmits the movement to the driving shaft 14 of the general mechanism of the circuit breaker thereby producing general opening of the circuit breaker by means of the general mechanism in a conventional manner.

When the general opening takes place the movable arm 16 pivots anti-clockwise and displaces the lever 13 and at the same time the actuating lever or actuating cage 21. The latter moves the locking lever 5, which takes up the re-cocked position shown in FIGURE 3. In this position the movable contact carrier or contact cage 7 is again locked in place relative to the actuatinglever or actuating cage 21 and the lever 13 is no longer in contact with the driving shaft 14 of the general mechanism of the circuit breaker. The multiphase circuit-breaker is reclosed by the clockwise rotation of the shaft 23 common to all the poles. Such clockwise rotation of the shaft 23 may be realized in any suitable manner, for example, manually, as is well known in the art. In each pole, the toggle device 1546 pushes the actuating lever or actuating cage 21 and at the same time the movable contact carrier or contact cage 7, which is locked thereto by the hook or nose portion 6, as is shown in FIGURE 3, until these members resume the position shown in FIGURE 1. In the open position of FIGURE 3, the locking of the contact carriers or contact cages 7 of the poles which have undergone the short-circuit is restored, on the one hand, while on the other hand the member 13 is retracted by the operative connection, of conventional construction, in the general circuit breaker mechanism, so that the general mechanism can be re-cocked to prepare for the subsequent closing operation.

The separation of the arcing contacts 118' and 119 by means of which the arc is struck, takes place in a manner which varies in accordance with the value of the over-load:

From the current value corresponding to the operating threshold of the direct tripping device until the value at which the contacts are repelled, which is fixed by the pressure of the pressure springs 31, the time of separation of the arcing contacts is equal to the response time of the tripping device plus the time movement of the movable contact carrier or contact cage 7 through the angle corresponding to the wiping of the said contacts; since springs 31 are conventional in the art, they are indicated only schematicaliy in the drawing.

The separation of the arcing contacts 118' and 119 is effected by repulsion at any higher current value. The are remains steady for a very short time between the arcing contacts 118 and 119 before being blown onto the horns 18. The tripping device is sufficiently rapid to prevent any re-closing of the contacts 118, 119, and 118, I19 realized by repulsion as a result of the electrodynamic forces.

Under the action of the electrodynamic forces exerted thereon, the arc is lengthened extremely quickly and is introduced into the group of plates situated above the contacts, in which it is subdivided into component arcs. The voltage, which depends upon the total length of the arc and upon the number of component arcs, increases under the same effect and stops the rise of current, which immediately commences to decrease. The are chute has, as compared with are chutes having simple plates, the considerable improvement that it provides channels for the evacuation of the hot gases. alternating with the arc channels. This arrangement has a double effect:

Increase in the open-ing for the liberation of hot gases, preventing them from flowing back and preventing restriking of the are at the level of the contacts;

Considerable increase in the metal gas-cooling. surfaces for accelerating the extinction of the arc, reducing the interrupting energy and decreasing flame effects above the chutes.

It will be obvious that the devices according to the invention are designed to permit all normal working operations. They are provided either with manual controls or with electrical controls of conventional nature and operatively associated with the general mechanism as is well known in the prior art. In addition to the direct electromagnetic tripping devices, these controls comprise magneto-thermaltripping devices for protection against light overloads.

The device according to the invention may be employed in alternating-current circuit breakers and in directcurrent circuit breakers.

There is therefore obtained by the application of the invention an interrupting device which has true advantages, notably that of being adapted to interrupt heavy short-circuit currents, while occupying a very small amount of space and affording very great safety in the circuit breaking.

I claim:

1. Ultra-rapid tripping device for a multipolar switch comprising for each pole movable contact means and fixed contact means separated by electrodynamic repulsion effect of a short circuit current, contact support means carrying said movable contact means which are independently released in case of short circuit through a respective pole, spring means acting on said movable contact support means in a direction corresponding to the opening of said contacts, devices for locking the movable contact support means, electromagnetic tripping devices individually controlling the locking devices of the respective movable contact support means in case of short circuit to free said movable contact support means while the contacts are separated by electrodynamic effect, said contact means having electrical conductors arranged with respect thereto to define a partial loop to aid in the repulsion of the contacts by the electrodynamic effect of said short circuit, and means mounting said movable contact means and associated electrical conductor connected thereto to define the said partial loop of a respective pole in such a manner that the net electrodynamic forces at all times produce a repulsion effect on the movable contact means irrespective of the conditionof the locking device and corresponding electromagnetic tripping device.

2. Ultra-rapid tripping device for a multipolar switch comprising for each pole movable contact means and fixed contact means separated by electrodynamic repulsion effect of a short circuit current, contact support means carrying said movable contact means which are independently released in case of short circuit through a respective pole, spring means acting on said movable contact support means in a direction corresponding to the opening of said contacts, devices for locking the movable contact support means, electromagnetic tripping devices individually controlling the locking devices of the respective movable contact support means in case of short circuit to free said movable contact support means while the contacts are separated by electrodynamic effect, said contact means having electrical conductors arranged with respect thereto to define a partial loop to aid in the repulsion of the contacts by the electrodynamic effect of said short circuit, a flexible electrical conductor being provided for each of said movable contact means and being connected thereto to form part of said loop, the entire length of said flexible conductor acting to separate said contact means when short circuit current passes therethrough.

3. A device according to claim 1, wherein said devices for locking the movable contact support includes actuating means for the latter, said movable contact support means being interlocked with the actuating means during resetting of the tripping device.

4. Ultra-rapid tripping device for a mul-tipolar switch having a common mechanical actuating mechanism for the poles of the switch and comprising, for each pole, movable contact means and fixed contact means separated by electrodynamic repulsion effect of a short circuit current, contact support means carrying said movable contact means Which are independently released in case of short circuit through a respective pole, spring means acting on said movable contact carrier means in the direction corresponding to the opening of said contact means, devices for locking the movable contact support means, electromagnetic tripping devices controlling the locking de vices of the movable contact support means in case of short circuit to free said movable contact support means While the contacts are separated by electrodynamic effect, said contact means having electrical conductors arranged with respect thereto to define a partial loop to aid in the repulsion of the contacts by the electrodynarnic effect of said short circuit, an actauting means at each of said poles for the respective movable contact support means, said actuating means being connected to said common mechanical opening mechanism, each of said poles including an independent lever means secured to the respective actuating means and actuated by a respective movable contact support means as the latter moves to open circuit position during short circuit operation, said lever means being actuated by the respective movable contact support means and controlling said common mechanism to open the poles of the switch.

5. Device according to claim 4, wherein pivot pin means are provided on the actuating means for pivotally supporting said lever means at a respective pole, said lever means being retracted during the opening of the switch to a position in which they are efiectively disengaged from said common mechanism to enable resetting of the tripping device, said last-mentioned position corresponding to the position of the actuating means in which the latter is again interlocked with the movable contact support means to enable reclosing of all the poles of the switch.

6. Ultra-rapid tripping device for a multipolar switch comprising for each pole movable contact means and fixed contact means separated by electrodynamic repulsion effect of a short circuit current, contact support means carrying said movable contact means switch are independently released in case of short circuit through a respective pole, devices for locking the movable contact support means, electromagnetic tripping devices controlling the locking devices of the movable contact sup port means in case of short circuit to free said movable contact support means while the contacts are separated by electrodynamic effect, said contact means having electrical conductors arranged with respect thereto to define a partial loop to aid in the repulsion of the contacts by the electrodynamic effect of said short circuit, actuating means for each of the movable contact support means, said locking devices including means for interlocking the actuating means with the movable contact support means while the tripping device is being reset, the interlocking means comprising a latching lever pivoted on a pin secured to the actuating means, said lever being provided with a catch to effect interlocking of the contact support means and actuating means, and spring means biasing the contact support means toward the open contact position.

7. Ultra-rapid tripping multipolar switch having a general actuating mechanism and comprising in each pole, movable contact means and fixed contact means normally separated by electrodynamic repulsion effect of a short circuit current, contact support means carrying said movable contact means which are independently released in case of short circuit through a respective pole, spring means acting upon the movable contact support means in the direction of opening of the contact means, actuating means for the movable contact support means which actuate the contact support means while the switch is being closed, locking means which are provided with a catch which insure the interlocking of the contact support means with the actuating means While the multipolar switch is being closed and the actuating means are held in the closed-contact position, electromagnetic tripping devices controlling the locking means of the movable contact support means in case of short circuit in order to free the contact support means, lever means, secured to the actuating means, which are displaced by an impact member of the contact support means upon opening of a respective contact support means and operable to control the general opening mechanism of the switch, a common control shaft for the poles of the switch, and mechanical interconnecting means between the actuating means of the movable contact support means and said shaft.

8. In a multi-pole circuit breaker having common actuating means for the movable contact means of all the poles, and comprising, for each pole stationary and movable contact means, a separate high-s eed tripping device for each pole comprising separate locking means for each pole for locking the respective stationary and movable contact means thereof, means for displacing a respective movable contact means in the direction toward the corresponding stationary contact means to cause engagement between the movable and stationary contact means in the locked condition of the respective pol-e, separate electromagnetic tripping means for each pole operatively connected with a respective locking means for rendering the respective locking means ineffectual and for effectively enabling opening movement of the corresponding movable contact means in case of short-circuit of a respective pole, means operatively associated with the contact means of a respective pole for aiding at all times in the opening movement of a corresponding movable contact means by the eleotrodynarnic forces of the short circuit including means Within said circuit breaker for mounting said movable contact means and electrical conductor leading thereto of a respective pole in such a manner as to form a partial loop in which electrodynamic forces caused by electric currents flowing therethrough produce at all time a net efiect seeking to separate the movable contact means from the stationary contact means in a direction opposite said first-mentioned direction, and connecting means operatively connecting the movable contact as sembly or" a respective pole including the movable contact means thereof and the locking means thereof with said common actuating means to effect opening movement of all of the other movable contact means upon opening one of said poles in the presence of a short-circuit in said one of said poles.

9. In a multi-pole circuit breaker having common actuating means for the movable contact means of all the poles, and comprising, for each pole stationary and movable contact means, a separate high-speed tripping device for each pole comprising separate locking means for each pole for locking the respective stationary and movable contact means thereof, means for displacing a respective movable contact means in the direction toward 8 the corresponding stationary contact means to cause en.- gagement between the movable and stationary contact means in the locked condition of the respective pole, separate electromagnetictripping means for each pole operatively connected with a respective locking means for rendering the respective locking means ineffectual and for effectively enabling opening movement of the corresponding movable contact means in case of short-circuit of a respective pole, means operatively associated with the contact means of a respective pole for adding at all times in the opening movement of a corresponding movable contact means by the electrodynamic forces of the short circuit including means within said circuit breaker for mounting said movable contact means and electrical conductor leading thereto of a respective pole in such a manner as to form a partial loop in which electrodynamic forces caused by electric currents flowing therethrough produce at all times a net effect seeking to separate the movable contact means from the stationary contact means in a direction opposite said first-mentioned direction, and connecting means operatively connectingrthe movable contact assembly of a respective pole including the movable contact means thereof and the locking means thereof with said common actuating means to effect opening movement of all of the other movable contact means upon opening one of said poles in the presence of a short-circuit in said one of said poles including means for automatically readying the movable contact means of all of said poles for another closing operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,727,631 Bruhlmann Sept. 10, 1929 1,728,020 Travers Sept. 10, 1929 2,127,813 Graves Aug. 23, 1938 2,329,003 Seaman Sept. 7, 1943 2,426,243 Scott Aug. 26, 1947 2,695,345 Scott Nov. 23, 1954 

1. ULTRA-RAPID TRIPPING DEVICE FOR A MULTIPOLAR SWITCH COMPRISING FOR EACH POLE MOVABLE CONTACT MEANS AND FIXED CONTACT MEANS SEPARATED BY ELECTRODYNAMIC REPULSION EFFECT OF A SHORT CIRCUIT CURRENT, CONTACT SUPPORT MEANS CARRYING SAID MOVABLE CONTACT MEANS WHICH ARE INDEPENDENTLY RELEASED IN CASE OF SHORT CIRCUIT THROUGH A RESPECTIVE POLE, SPRING MEANS ACTING ON SAID MOVABLE CONTACT SUPPORT MEANS IN A DIRECTION CORRESPONDING TO THE OPENING OF SAID CONTACTS, DEVICES FOR LOCKING THE MOVABLE CONTACT SUPPORT MEANS, ELECTROMAGNETIC TRIPPING DEVICES INDIVIDUALLY CONTROLLING THE LOCKING DEVICES OF THE RESPECTIVE MOVABLE CONTACT SUPPORT MEANS IN CASE OF SHORT CIRCUIT TO FREE SAID MOVABLE CONTACT SUPPORT MEANS WHILE THE CONTACTS ARE SEPARATED BY ELECTRODYNAMIC EFFECT, SAID CONTACT MEANS HAVING ELECTRICAL CONDUCTORS ARRANGED WITH RESPECT THERETO TO DEFINE A PARTIAL LOOP TO AID IN THE REPULSION OF THE CONTACTS BY THE ELECTRODYNAMIC EFFECT OF SAID SHORT CIRCUIT, AND MEANS MOUNTING SAID MOVABLE CONTACT MEANS AND ASSOCIATED ELECTRICAL CONDUCTOR CONNECTED THERETO TO DEFINE THE SAID PARTIAL LOOP OF A RESPECTIVE POLE IN SUCH A MANNER THAT THE NET ELECTRODYNAMIC FORCES AT ALL TIMES PRODUCE A REPULSION EFFECT ON THE MOVABLE CONTACT MEANS IRRESPECTIVE OF THE CONDITION OF THE LOCKING DEVICE AND CORRESPONDING ELECTROMAGNETIC TRIPPING DEVICE. 